Meet Jared Kaplan, the top Anthropic scientist who predicted the core of today's AI doom debate

At the center of the debate over AI-driven catastrophe, there's Anthropic. At the center of Anthropic, there's Jared Kaplan.

The Anthropic cofounder sounded the alarm on AI late last year: No one knows what will happen if frontier developers get AI to the point where it fully trains itself. He told the Guardian that letting AI train itself could lead to an "intelligence explosion," but it's also the "ultimate risk" and "maybe the biggest decision or scariest thing to do." The decision point for that process, he said, could arrive between 2027 and 2030.

We're just about on schedule. As 2026 winds down, state-of-the-art AI systems are already helping researchers build models at both Anthropic and OpenAI.

A physicist-turned-AI-researcher, Kaplan left OpenAI to cofound Anthropic with CEO Dario Amodei and others in 2021. He gives the worries about AI getting dangerously out of control some authoritative credence — his chief science officer role at Anthropic is one of tech's most influential jobs. He oversees technical research, AI safety, and Anthropic's "responsible scaling policy." It's his job to mitigate the risks of powerful AI.

More people are listening to Kaplan's warning. Jacob Coxon, a researcher who resigned from Anthropic earlier this month, referred directly to letting AI train itself in his now-viral X post, writing that OpenAI and Anthropic are "gambling with our lives." Around two-thirds of Americans now think there's a risk AI could destroy humanity, a Politico poll found last week.

The chatter has reached DC, too, with lawmakers proposing new legislation and paying new attention to long-running AI safety concerns. Jeffrey Ladish, a former Anthropic engineer and founder of the AI safety nonprofit Palisade Research, told Business Insider that when meeting with lawmakers, he referred back to Kaplan's remarks — specifically the idea that having AI train itself could let it get out of control.

"It's good for more people to hear from more engineers, researchers, people in the company who, it's not their job to do company PR," said Ladish. "It's their job to figure things out."

Now a billionaire, Kaplan keeps an understated public profile even as AI researchers who worked with him say he serves as a major leader inside Anthropic. The company declined to make him available for an interview.

AI is Kaplan's second career. He met Amodei when the two attended Harvard for physics and Princeton for biophysics, respectively, for graduate school. They ended up carpooling to an event and bonded over the then-new charity evaluator GiveWell, Kaplan recounted at a Hertz Foundation talk last year. They became friends and lived together as roommates in San Francisco at one point.

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By then, Kaplan was already showing promise. He'd co-authored an influential physics paper called "The Effective Field Theory of Inflation." He worked at a Department of Energy lab in Menlo Park, then at Stanford, before heading back east to join the faculty at Johns Hopkins in 2012.

Nima Arkani-Hamed, Kaplan's advisor at Harvard, remembers being skeptical about the inflation paper before it scooped a similar paper from a famous Nobel laureate. Arkani-Hamed told Business Insider that Kaplan's strength as a physicist was in following where a "big, conceptual point" would lead, and this set him up for AI.